Passthrough version

platformio.ini

@@ -36,6 +36,7 @@ monitor_speed = 230400
 ; The entry sketch (app/wii5_buoy/wii5_buoy.ino) is pulled in by pio_main.cpp.
 build_src_filter =
     +<*.cpp>
+    -<pio_main_passthrough.cpp>
 
 ; The project's own headers are included with angle brackets (<WII5.h>, ...),
 ; so the repo root must be on the include path. Software version/commit are
@@ -65,6 +66,16 @@ lib_deps =
     arduino-libraries/SD
     adafruit/RTClib
 
+; Lean pass-through variant: keeps the Maths CPU powered on and provides
+; bidirectional raw serial passthrough to the Iridium modem from the USB
+; console.  Excludes the full wii5_buoy main (pio_main.cpp) so setup()/loop()
+; come from pio_main_passthrough.cpp instead.
+[env:wii5_passthrough]
+extends = env:wii5_buoy
+build_src_filter =
+    +<*.cpp>
+    -<pio_main.cpp>
+
 ; LoRa-enabled variant (experimental). This path additionally depends on the
 ; Sh3dNode networking stack (sh3dNodeNetwork / SH3D_NODE_Packet_* / RH_RF95),
 ; which is NOT bundled in this repository, so the env does not build as-is.